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Mina W Morcos,1 James L Howard,2 Brent Lanting,2 Steven MacDonald,2 Douglas Naudie,2 Richard McCalden,2 Edward M Vasarhelyi2 1Division of Orthopaedic Surgery, Department of Surgery, University of Toronto, Toronto, ON, Canada; 2Division of Orthopaedic Surgery, Department of Surgery, Western University London Health Sciences Center University Hospital, London, ON, CanadaCorrespondence: Edward M VasarhelyiDivision of Orthopaedic Surgery, Department of Surgery, Western University London Health Sciences Center University Hospital, 339 Windermere Road, PO Box 5339, London, Ontario N6A 5A5, CanadaTel +1 519 663-3413Fax +1 519 663-3417Email edward.vasarhelyi@lhsc.on.caPurpose: The necessity of stemmed components when performing a varus-valgus constrained (VVC) primary total knee arthroplasty (TKA) is unclear. The purpose of this study is to compare the outcomes of primary VVC TKA with and without stems at a minimum of two years.Methods: Patients in our prospectively collected database with primary VVC TKAs were identified. Patient demographics, prosthesis data, time in vivo, characteristics of revision, and radiographs and PROMs were compared between the stemmed and un-stemmed cohorts.Results: Sixty-five patients with 69 primary VVC TKAs were identified; 17 were implanted with stems and 52 without stems. Five of the stemmed TKAs (5/17) required revision at 15.1 years, while only one of the un-stemmed TKA (1/52) required a revision at 21.6 years (p=0.003) for aseptic loosening. Of the 5 stemmed TKAs requiring revision, 3 were for aseptic loosening and 2 were for PPJI. The un-stemmed cohort had a significantly higher final total KSS (p=0.048).Conclusion: There was no increase in aseptic loosening or revision surgery in patients with non-stemmed primary VVC TKA compared to those with stemmed VVC TKA at mid-term follow-up. Utilizing non-stemmed TKA with VVC in appropriate cases is safe and may reduce cost, shorten operative time, and preserve bone-stock.Keywords: total knee arthroplasty, knee instability, stemmed implants, constraints

Osteopetrosis is a rare metabolic bone disease, characterized by dysfunction of osteoclasts, resulting in increased bone density and brittleness leading to pathological fractures and bone deformities. Hip and knee osteoarthritis (OA) are common long-term complications in patients with osteopetrosis. Joint arthroplasty surgery remains an effective and recommended treatment for these patients with an end-stage OA because it provides favorable outcomes. However, in osteopetrosis, joint arthroplasty surgery carries an increased risk of complications, and specific preoperative and perioperative considerations are required to deal with the technical challenges related to the disease. The aim of this article was to review some of the key aspects of osteopetrosis, provide technical recommendations, and answer clinically relevant questions related to hip and knee arthroplasty surgery., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Purpose: While restricted kinematic alignment (rKA) total knee arthroplasty (TKA) with cemented implants has been shown to provide a similar survivorship rate to mechanical alignment (MA) in the short term, no studies have reported on the long-term survivorship and function., Methods: One hundred four consecutive cemented cruciate retaining TKAs implanted using computer navigation and following the rKA principles proposed by Vendittoli were reviewed at a minimum of 10 years after surgery. Implant revisions, reoperations and clinical outcomes were assessed using knee injury and osteoarthritis outcome score (KOOS), forgotten joint score (FJS), patients' satisfaction and joint perception questionnaires. Radiographs were analyzed to identify signs of osteolysis and implant loosening., Results: Implant survivorship was 99.0% at a mean follow-up of 11.3 years (range: 10.3-12.9) with one early revision for instability. Patients perceived their TKA as natural or artificial without limitation in 50.0% of cases, and 95.3% were satisfied or very satisfied with their TKA. The mean FJS was 67.6 (range: 0-100). The mean KOOS were as follows: pain 84.7 (range: 38-100), symptoms 85.5 (range: 46-100), function in daily activities 82.6 (range: 40-100), function in sport and recreation 35.2 (range: 0-100) and quality of life 79.1 (range: 0-100). No radiological evidence of implant aseptic loosening or osteolysis was identified., Conclusion: Cemented TKA implanted with the rKA alignment protocol demonstrated excellent long-term implant survivorship and is a safe alternative to MA to improve patient function and satisfaction., Level of Evidence: IV, continuous case series with no comparison group., (© 2024 The Author(s). Knee Surgery, Sports Traumatology, Arthroscopy published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

Background: This study reports the minimum 10 years results of total hip arthroplasty (THA) performed using a monoblock acetabular component with a large-diameter head ceramic-on-ceramic bearing., Methods: Of the 276 THAs included in this study, there were eleven deaths and 27 patients lost to follow up (11%) during the follow-up, leaving 237 (85%) hips available for review at a mean of 10.5 years (range, 10 to 12) postoperatively. Reoperations, implant revisions, adverse events, clinical outcomes, radiographic evaluation, and whole blood metal ion levels were assessed at the last follow-up., Results: After a minimum of 10 years, implant survivorship was 98.7%. There were 3 revisions (1.3%): one for insufficient acetabular cup primary fixation, one traumatic periprosthetic acetabular fracture, and one probable deep chronic infection. No dislocation or ceramic implant fracture was observed. The mean University of California at Los Angeles activity score, Western Ontario and McMaster Universities Osteoarthritis Index score, and Forgotten Joint Score were 5.6 (2 to 10), 90.1 (9 to 100), and 79.2 (4 to 100), respectively. All patients (100%) were satisfied or very satisfied. Since implantation, 43% of patients reported hearing a squeaking noise from the prosthesis. But all patients who reported squeaking were satisfied with the surgery. The mean titanium level was 2.2 μg/L (1.1 to 5.6). No progressive radiolucent lines, osteolysis, or implant loosening signs were observed at the last radiographic evaluation., Conclusions: A large-diameter head ceramic-on-ceramic THA provides outstanding long-term (minimum 10 years) implant survivorship with unrestricted activity while avoiding implant impingement, liner fracture, and hip instability. Functional outcomes, satisfaction, and joint perception were excellent. Although the incidence of squeaking was high, it did not affect patient satisfaction or function. The systemic titanium levels were low, related to unavoidable passive corrosion of implant surfaces, and did not reveal any indirect signs of trunnionosis., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Total knee arthroplasty (TKA) is considered the gold standard treatment for patients who have advanced hemophilic knee arthropathy. However, special considerations are required for these patients. This prospective study reports on the need for soft-tissue procedures, implant types, complication rates, mean 53.3 months implant survivorship, and patient-reported outcome measures of TKA in hemophilic patients., Methods: There were twenty primary TKAs that were performed on 15 hemophilic patients from 2012 to 2023. The mean follow-up was 53.3 months (range, 6 to 128). The necessity for additional soft tissue procedures, implant type, complications, and revision rates were recorded. Knee Injury and Osteoarthritis Outcome Score, Knee Society Score, Hemophilia-specific Quality of Life Questionnaire for Adults, Hemophilia Activities List, and range of motion, were compared preoperatively and at the last follow-up., Results: At the last follow-up, implant survivorship was 90%. There were 2 revisions: one for aseptic loosening and one for periprosthetic joint infection. Additional soft tissue procedures included 2 quadriceps snips (10%). Tibial augments, tibial stubby stems, and both tibial and femoral traditional stems were used in one (5%), 4 (20%), and one (5%) TKAs, respectively. A constrained posterior-stabilized bearing was necessary in one case. Clinically and statistically significant improvements were found between the preoperative and final follow-up values of all patient-reported outcome measures, knee flexion (73 versus 108 °, P < 0.001), and flexion contracture (11 versus 4 °, P = 0.002)., Conclusions: This study showed that TKA, in patients who have hemophilic knee arthropathy, is a reliable treatment option that improves knee function and patients' quality of life with acceptable implant survival rates at midterm follow-up (mean 53.3 months). Standard implants and approaches can be used in most cases. Despite good outcomes, hemophilic patients carry additional risks for complications that require specific considerations. It is paramount for these patients to be treated in specialized centers by experienced surgeons to achieve good results., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Large-diameter head (LDH) total hip arthroplasty (THA) with a monobloc acetabular component improves hip stability. However, obtaining initial press-fit stability is quite challenging in atypical acetabula. The purpose of this study was to assess primary and secondary fixation of monobloc cups in atypical acetabula., Methods: In this consecutive case series, the local arthroplasty database was used to retrospectively identify patients with secondary osteoarthritis who underwent primary hip replacement with press-fit only LDH monobloc acetabular components between 2005 and 2018 and who had a minimum of 2 years of follow-up. Radiographic evaluation was performed at last follow-up, and patient-reported outcome measures (PROMs) were assessed with the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Forgotten Joint Score (FJS), and the Patient's Joint Perception (PJP) question., Results: One hundred and six LDH THAs and 19 hip resurfacings were included in the study. Preoperative diagnoses included hip dysplasia (36.8%), Legg-Calve-Perthes disease (32.0%), osteoarthritis with acetabular deficiency (17.6%), periacetabular osteotomy (8.0%), arthrodesis (4.0%), and osteopetrosis (1.6%). After a mean follow-up of 9.2 years, no aseptic loosening of the acetabular component was recorded nor observed on radiologic review. There were 13 (10.4%) revisions unrelated to the acetabular component fixation. The mean WOMAC and FJS scores were 9.2 and 80.9, respectively. In response to the PJP question, 49.4% of the patients perceived their hip as natural, 19.1% as an artificial joint with no restriction, 31.5% as an artificial joint with restriction, and none as a non-functional joint., Conclusion: Primary press-fit fixation of monobloc acetabular components with LDH implanted in atypical acetabula led to secondary fixation in all cases with low revision and complication rates and great functional outcomes. With careful surgical technique and experience, systematic use of supplemental screw fixation is not essential in THA with atypical acetabula., Competing Interests: Competing interests:: M.-O. Kiss has received unrestricted research funding paid to his institution from Stryker, Johnson & Johnson, Smith & Nephew and Zimmer. P.-A. Vendittoli has received research funding from Zimmer, Smith & Nephew, Johnson & Johnson, and Stryker, royalties from MicroPort, and consulting and speaker fees from Johnson & Johnson. No other competing interests were declared., (© 2024 CMA Impact Inc. or its licensors.)

Advanced hemophilic knee arthropathy is a frequent and devastating manifestation of severe hemophilia with significant implications for activities of daily living. Hemophilic arthropathy is caused by repeated bleeding, resulting in joint degeneration, pain, deformity and disability. In patients with hemophilia and advanced disease, total knee arthroplasty (TKA) has proven to be the most successful intervention, improves physical function and reduces knee pain. Hemophilic patients carry additional risks for complications and required specific pre/postoperative considerations. Expert treatment center should be used to improve patient outcome. Hemophilic patients present significant surgical challenges such as joint destruction, bone loss, severe ankylosis and oligoarticular involvement. The surgeon performing the arthroplasty must be experienced to manage such problems.

Current limitations in total knee arthroplasty (TKA) function and patient satisfaction stimulated us to question our practice. Our understanding of knee anatomy and biomechanics has evolved over recent years as we now consider that a more personalized joint reconstruction may be a better-targeted goal for TKA. Implant design and surgical techniques must be advanced to better reproduce the anatomy and kinematics of native knees and ultimately provide a forgotten joint. The availability of precision tools as robotic assistance surgery can help us recreate patient anatomy and ensure components are not implanted in a position that may compromise long-term outcomes. Robotic-assisted surgery is gaining in popularity and may be the future of orthopedic surgery. However, moving away from the concept of neutrally aligning every TKA dogma opens the door to new techniques emergence based on opinion and experience and leads to a certain amount of uncertainty among knee surgeons. Hence, it is important to clearly describe each technique and analyze their potential impacts and benefits. Personalized TKA techniques may be classified into 2 main families: unrestricted or restricted component orientation. In the restricted group, some will aim to reproduce native ligament laxity versus aiming for ligament isometry. When outside of their boundaries, all restricted techniques will induce anatomical changes. Similarly, most native knee having asymmetric ligaments laxity between compartments and within the same compartment during the arc of flexion; aiming for ligament isometry induces bony anatomy changes. In the current paper, we will summarize and discuss the impacts of the different robotic personalized alignment techniques, including kinematic alignment (KA), restricted kinematic alignment (rKA), inverse kinematic alignment (iKA), and functional alignment (FA). With every surgical technique, there are limitations and shortcomings. As our implants are still far from the native knee, it is primordial to understand the impacts and benefits of each technique. Mid to long data will help us in defining the new standards., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Morcos, Uhuebor and Vendittoli.)

Background: Instability is a major cause of failure of revision total hip arthroplasty (THA) which can be avoided with the use of monobloc press-fit cups with large diameter heads (LDH)., Objective: This consecutive case series analyses whether LDH monobloc components are a safe and clinically beneficial option for revision THA., Methods: This consecutive case series includes 47 revision THA with LDH monobloc acetabular cup. Acetabular bone defects were Paprosky type I (42), type IIA (2) and type IIC (3). The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Forgotten Joint Score (FJS) and the Patient's Joint Perception (PJP) scores were analysed and a radiographic evaluation for signs of implant dysfunction was performed., Results: After a mean follow-up of 4.5 years, there were 5 (10.6%) acetabular cup re-revisions: 2 loss of primary fixation and 3 instabilities. Implant survivorship at 4-years was 89.4% (95% CI: 89.3 to 89.5). Recurrent hip dislocation was reported in 1 patient (2.1%) and remains under conservative treatment. The mean WOMAC and FJS were 19.5 (16.8; 0.0 to 58.3) and 57.3 (28.9; 6.3 to 100.0), respectively. Regarding the PJP, 3 (8.8%) patients perceived their hip as natural, 8 (23.5%) as an artificial joint with no restriction, 14 (41.2%) with minor restriction and 9 (26.5%) with major restriction., Conclusion: In cases of revision THA with limited bone loss, press-fit primary fixation with LDH monobloc acetabular components are valuable options that offer excellent mid-term out-comes with low re-revision and joint instability rates., Competing Interests: PAV declares being a consultant for Stryker and Johnson & Johnson; receives royalties from Microport; and received research funding from Zimmer, Smith & Nephew, Johnson & Johnson, and Stryker. MOK declares he received research funding from Zimmer, Smith & Nephew, Johnson & Jonhson and Styker. PAS, SS and BB declare that they have no conflict of interest.

Background: The purpose of this study was to evaluate the influence of discharge timing on 30-day complication rates following total hip arthroplasty., Methods: We identified patients who underwent total hip arthroplasty between 2011 and 2017 from the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database. Using propensity score matching, we matched patients who were discharged from the hospital on the day of surgery to those discharged on postoperative days 1, 2, 3 and 4, respectively. We used multivariable logistic regression to determine if the rates of complications and readmission differed depending on length of stay., Results: We identified 141 594 patients who underwent total hip arthroplasty (average age 64.7 [standard deviation (SD) 11.4] yr) from the NSQIP database. The average length of stay was 2.3 days and decreased from 2.8 (SD 0.7) days in 2011 to 1.9 (0.9) days in 2017. The adjusted odds of a major complication increased by 1.33 (1.09-1.61) and 1.41 (1.05-2.21) for patients discharged on postoperative day 3 and 4, respectively, compared with patients discharged on postoperative day 2. Similarly, the adjusted odds of a minor complication increased by 1.22 (1.03-1.43) and 1.58 (1.11-2.26) for patients discharged on postoperative days 3 and 4, respectively, compared with those discharged on postoperative day 2. We found no difference in the risk of major or minor complications between patients discharged on the day of surgery or postoperative day 1 compared with patients discharged on postoperative day 2. We also found that a length of stay of 3 or 4 days increased the risk of readmission (odds ratio [OR] 1.15, 95% confidence interval [CI] 1.03-1.29, and OR 1.18, 95% CI 1.08-1.85, respectively) compared with a length of stay of 2 days., Conclusion: Our data suggest that discharge on postoperative days 0-2 is associated with the lowest risk of 30-day complications following total hip arthroplasty. These findings support early discharge after total hip arthroplasty; however, more prospective clinical data are required to determine the optimal length of stay following total hip arthroplasty., Competing Interests: Competing interests: E. Schemitsch has received consulting fees from Stryker, Smith & Nephew and Depuy Synthes and institutional research support from Stryker, Zimmer, Depuy Synthes and Smith & Nephew. No other competing interests were declared., (© 2022 CMA Impact Inc. or its licensors.)

Damage to limbal epithelial stem cells can lead to limbal stem cell deficiency (LSCD). Current autologous treatment procedures for unilateral LSCD bear a significant risk of inducing LSCD in the donor eye. This complication can be avoided by grafting a stem cell containing cultured autologous corneal epithelium (CACE). The primary objective of this study was to demonstrate the safety of CACE grafted on eyes with LSCD. The secondary objective was to assess the efficacy of a CACE graft in restoring a self-renewing corneal surface with adequate anatomic structures, as well as improving the best corrected visual acuity (BCVA). Fifteen patients were grafted with a CACE on a fibrin gel produced from a 3 mm 2 limbal biopsy harvested from the donor eye. Data were collected at baseline and after grafting. Follow-ups from 1 to 5 years were conducted. No major adverse events related to the CACE graft were observed. For every visit, an anatomic score based on corneal opacity as well as central vascularization and a functional score based on BCVA were determined. Safety was demonstrated by the low occurrence of complications. Anatomical (93%) and functional (47%) results are promising for improving vision in LSCD patients. Combined functional success and partial success rates with inclusion of BCVA were 53% [CI95: 27-79%] one year after CACE grafting. At the last follow-up, 87% [CI95: 60-98%] of the patients had attained corneal clarity. The outcomes demonstrate the safety of our technique and are promising regarding the efficacy of CACE in these patients.

Hip arthroplasty is a common procedure in elective orthopaedic surgery that has excellent outcomes. Hip replacement surgery aims to create a "forgotten" joint, i.e., a pain-free joint akin to a native articulation. To achieve such goals, hip arthroplasty must be personalised. This is achieved by restoring: the centre of rotation of the native hip; leg length equality; femoral offset; femoral orientation; soft tissue tension; joint stability with an unrestricted hip range of motion; and having appropriate stress transfer to the bone. In addition, the whole pathway should provide an uneventful and swift postoperative recovery and lifetime implant survivorship with unrestricted activities. At our institution, the preferred option is a personalized total hip arthroplasty (THA) with a large diameter head (LDH) using either monobloc or dual-mobility configuration for the acetabular component. LDH THA offers an impingement-free range of motion and a reduced risk of dislocation. The larger head-neck offset allows for a supraphysiologic range of motion (ROM). This can compensate for a patient's abnormal spinopelvic mobility and surgical imprecision. Additionally, LDH bearing with a small clearance exerts a high suction force, which provides greater hip micro-stability. With appropriate biomechanical reconstruction, LDH THA can restore normal gait parameters. This results in unrestricted activities and higher patient satisfaction scores. We use LDH ceramic on ceramic for our patients with a life expectancy of more than 20 years and use LDH dual mobility bearings for all others.

Background: The aim of this study was to evaluate the influence of operating time on complications and readmission within 30 days of total knee arthroplasty (TKA) and to determine if there were specific time intervals associated with worse outcomes., Methods: The American College of Surgeons’ National Surgical Quality Improvement Program database was used to identify patients 18 years of age and older who underwent TKA between 2006 and 2017, using procedural codes. Patient demographic characteristics, operation length and 30-day major and minor complication and readmission rates were captured. We used multivariable regression to determine if the rates of complications and readmission differed depending on the length of the operation, while adjusting for relevant covariables., Results: A total of 263 174 patients who underwent TKA were identified from the database. Their mean age was 66.8 (standard deviation 9.7) years. Within 30 days of the index procedure, 5700 patients (2.2%) experienced a major complication, 5185 (2.0%) experienced a minor complication and 7730 (3.1% of 249 746 patients from 2011 to 2017) were readmitted. Mean operation length was 91.7 minutes (range 30–240 min). After adjustment for relevant covariables, an operating time of 90 minutes or more was a significant predictor of major and minor complications as well as readmission. There was no difference in the odds of complications or readmission for operations lasting 30–49, 50–69 or 70–89 minutes (p > 0.05)., Conclusion: Our data suggest that operating times of 90 minutes or more may be associated with an increase in the 30-day odds of complications and readmission following TKA. Further studies are needed to confirm our findings and determine the influence of surgical time on outcomes when there is increased case complexity., Competing Interests: E. Schemitsch has received personal fees from Stryker and ITS, other support from Stryker, ITS and Acumed and nonfinancial support from Biocomposites. No other competing interests were declared., (© 2021 CMA Joule Inc. or its licensors)

Background: Currently, the gold standard treatment for periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) is 2-stage revision, but few studies have looked at the economic impact of PJI on the health care system. The objective of this study was to obtain an accurate estimate of the institutional cost associated with the management of PJI in TKA and to assess the economic impact of PJI after TKA compared to uncomplicated primary TKA., Methods: We identified consecutive patients in our institutional database who had undergone 2-stage revision TKA for PJI between 2010 and 2014 and matched them on age and body mass index with patients who had undergone uncomplicated primary TKA over the same period. We calculated all costs associated with the 2 procedures and compared mean costs, length of stay, clinical visits and readmission rates between the 2 groups., Results: There were 73 patients (mean age 68.8 [range 48-91] yr) in the revision TKA cohort and 73 patients (mean age 65.9 [range 50-86] yr) in the primary TKA cohort. Two-stage revision surgery was associated with a significantly longer hospital stay (mean 22.7 d v. 3.84 d, p < 0.001), more outpatient clinic visits (mean 8 v. 3, p < 0.001), more readmissions (29 v. 0, p < 0.001) and higher overall cost (mean $35 429.97 v. $6809.94, p < 0.001) than primary TKA., Conclusion: Treatment for PJI after TKA has an enormous economic impact on the health care system. Our data suggest a fivefold increase in expenditure in the management of this complication compared to uncomplicated primary TKA., Competing Interests: J. Howard reports grants from Stryker and DePuy Synthes, personal fees from Stryker, DePuy Synthes, Smith & Nephew and Intellijoint Surgical, and institutional research support from Stryker, DePuy Synthes, Smith & Nephew, Zimmer Biomet and MicroPort, outside the submitted work. He holds stock in PersaFix Technologies. E. Vasarhelyi reports grants from DePuy Synthes, personal fees from DePuy Synthes, Zimmer Biomet and Hip Innovation Technology, and institutional research support from DePuy Synthes, Zimmer Biomet, Smith & Nephew and Stryker. No other competing interests were declared., (© 2021 Joule Inc. or its licensors.)

Objective: Direct anterior approach (DAA) is becoming a popular option for both primary and revision total hip arthroplasty (THA). Adequate exposure is crucial in the setting of revision THA. The purpose of this article is to describe two different techniques for expanded femoral exposure through the DAA, the anterior extended trochanteric osteotomy and anterior cortical window., Methods: Extensile exposure were carried out in cadavers, using the contralateral hip as a control. The exposure and technical viability were assessed., Results: It was demonstrated that both extensile techniques can be carried out safely., Conclusions: Extensile exposures including femoral osteotomies can be safely carried out for revision THA via DAA., Competing Interests: The Authors declare that there is no conflict of interest., (© 2020 Professor P K Surendran Memorial Education Foundation. Published by Elsevier B.V. All rights reserved.)

Background: Periprosthetic joint infection (PJI) is the third leading cause of total hip arthroplasty (THA) failure. Although controversial, 2-stage revision remains the gold standard treatment for PJI in most situations. To date, there have been few studies describing the economic impact of PJI in today’s health care environment. The purpose of the current study was to obtain an accurate estimate of the institutional cost associated with the management of PJI in THA and to assess the economic burden of PJI compared with primary uncomplicated THA., Methods: We conducted a review of primary THA cases and 2-stage revision THA for PJI at our institution. Patients were matched for age and body mass index. All costs associated with each procedure were recorded. Descriptive statistics were used to summarize the collected data. Mean costs, length of stay, clinic visits and readmission rates associated with the 2 cohorts were compared., Results: Fifty consecutive cases of revision THA were matched with 50 cases of uncomplicated primary THA between 2006 and 2014. Compared with the primary THA cohort, PJI was associated with a significant increase in mean length of hospital stay (26.5 v. 2.0 d, p < 0.001), mean number of clinic visits (9.2 v. 3.8, p < 0.001), number of readmissions (12 v. 1, p < 0.001) and average overall cost (Can$38 107 v. Can$6764, t = 8.3, p < 0.001)., Conclusion: Treatment of PJI is a tremendous economic burden. Our data suggest a 5-fold increase in hospital expenditure in the management of PJI compared with primary uncomplicated THA., Competing Interests: J. Howard reports receiving grants from Stryker and DePuy, personal fees from Stryker, DePuy, Smith & Nephew and Intellijoint, and institutional research support from Stryker, DePuy, Smith & Nephew, Zimmer and MicroPort, all outside the submitted work. He holds stock in PersaFix Technologies. B. Lanting reports receiving personal fees from Smith & Nephew, Stryker, DePuy, Integra and Intellijoint, and institutional support from Smith & Nephew, DePuy, Stryker and Zimmer, all outside the submitted work. E. Vasarhelyi reports receiving grants from DePuy, grants and personal fees from DePuy and Hip Innovation Technology, and institutional support from DePuy, Stryker and Smith & Nephew, all outside the submitted work. No other competing interests were declared., (© 2020 Joule Inc. or its licensors)

Total knee arthroplasty (TKA) profoundly influences knee biomechanics. Using an arbitrary (often 3° to 5°) posterior tibial slope (PTS) in all cases seldom will restore native slope. This study examined whether the native PTS could be reproduced in cruciate-retaining TKA and how this would influence clinical outcome. Radiographic and clinical outcomes of 215 consecutive TKAs using the PFC sigma cruciate-retaining implant were evaluated. The tibial bone cut was planned to be made parallel to the native anatomical slope in the sagittal plane. The PTS was measured with reference to the proximal tibial medullary canal (PTS-M) and the proximal tibial anterior cortex (PTS-C) on true lateral radiographs using a picture achieving and communication system. Knee range of motion (ROM), Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Short Form Health Survey (SF-12) were evaluated. Mean preoperative PTS-M was 6.9°±3.3°, and mean postoperative PTS-M was 7.0°±2.4°. Mean preoperative PTS-C was 12.2°±4.2°, and mean postoperative PTS-C was 12.6°±3.4°. Preoperative and postoperative PTS were not significantly different for both techniques (P>.05). An arbitrary 3° as an acceptable range for PTS-M was achieved in 144 knees (67%) (group 1), and 71 knees (33%) had a difference of more than 3° (group 2). Group 1 had a significantly larger gain in ROM (P=.04) as well as improved Knee Society, WOMAC, and SF-12 physical scores compared with group 2 (P<.01). The modified surgical technique reproduced the native tibial slope in cruciate-retaining TKA. Reproduction of the native PTS within 3° resulted in better clinical outcomes manifested by gain in ROM and knee functional outcome scores. [Orthopedics. 2020; 43(1):e21-e26.]., (Copyright 2019, SLACK Incorporated.)

This study evaluates physical activity in patients with advanced hip OA using Fitbit and whether a correlation exists between the number of steps taken per day (SPD) and the reported outcome., Methods: 122 patients were prospective enrolled. Patient-reported outcomes were collected. Patients were asked to wear a Fitbit for 24 h a day on seven consecutive days., Result: The mean number of SPD was 5721 ± 3920. The UCLA, HHS and SF-12 PCS demonstrated a statistically significant positive correlation with the SPD., Conclusion: Wearable technology is reliable in objectively measuring the level of physical activity in hip OA and correlates with reported outcomes., Competing Interests: All the Authors declare that they have no conflict of interest., (© 2019 Professor P K Surendran Memorial Education Foundation. Published by Elsevier B.V. All rights reserved.)

Case: We present 2 cases of femoral neck fracture (FNF) in patients with osteogenesis imperfecta (OI) with a previously placed intramedullary nail (IMN). Case 1: A 12-year-old girl who sustained a right FNF after spine surgery. Case 2: An 18-year-old boy who sustained a right FNF after IMN of the left side. Both patients underwent our modified surgical technique as described below. Both patients recovered well overall., Conclusions: FNF in patients with OI poses a significant challenge especially in the presence of an IMN. Here, we describe a surgical technique that provides stable fixation with a less stress riser effect by bypassing the screws and a previously placed nail.

Background: Minimal to extensive medial soft tissue releases are part of the exposure and achieving adequate varus knee balance in total knee arthroplasty (TKA). However, the effect of these releases on knee kinematics and patient-reported outcomes is unclear. Our objective was to compare the postoperative in vivo tibiofemoral contact kinematics of a posterior-stabilized TKA between patients who received minimal medial soft tissue releases intraoperatively to those who received extensive releases. We also compared these groups using patient-reported outcomes., Methods: A prospective imaging study was performed in a single-center over a 14-month period. Patients with end-stage osteoarthritis and varus deformity undergoing primary TKA were included. Baseline data were collected 1 month before surgery. The radiostereometric analysis imaging took place at least 1 year postoperatively and composed of weight-bearing radiographic stereo examinations of knee flexion starting in full extension and in 20° increments of flexion to a maximum of 120°. Intraoperative medial soft tissue releases were recorded. Patient-reported outcomes used included Short-Form 12, Western Ontario and McMaster Osteoarthritis Index, and Knee Society Score., Results: Fifty-one patients were included in the statistical analysis. Demographic characteristics were similar between all. Patients were divided into 3 groups depending on the amount of releases they received. No statistically significant differences in tibiofemoral contact positions or excursions on the medial or lateral condyles were found throughout flexion from 0° to 120°. Postoperative patient-reported outcome scores were not different., Conclusion: Correcting severe varus deformities with extensive medial soft tissue release largely did not alter knee kinematics or clinical outcome scores compared to those with minimal soft tissue release., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Study Design: Ambispective cohort study., Objective: Patients spend on average 3 to 7 days in hospital after lumbar fusion surgery. Patients who are unable to be discharged home may require a prolonged hospital stay while awaiting a bed at a rehabilitation facility, adding cost and imposing a considerable burden on the health care system. Our objective is to identify patient or procedure related predictors of discharge destination for patients undergoing posterior lumbar fusion., Methods: Analysis of data from the Canadian Spine Outcomes and Research Network. Patients who underwent lumbar fusion for degenerative pathology between 2008 and 2015 were identified. Multivariable logistic regression analysis was used to identify independent predictors of the discharge destination., Results: A total of 643 patients were identified from the database, 87.1% of the patients (N = 560) were discharged home while 12.9% (N = 83) required discharge to nonhome facilities. Using multivariate logistic regression analysis, the predictors for discharge to a facility rather than home were identified including: increasing age (odds ratio [OR] 1.045, 95% confidence interval [CI] 1.017 -1.075, P < .002), increasing body mass index (BMI) (OR 1.069, 95% CI 1.021 -1.118, P < .004), increasing disability score (OR 1.025, 95% CI 1.004 -1.046, P < .02), living alone preoperatively (OR 1.916, 95% CI 1.004-3.654, P < .05), increasing operating time (OR 1.005, 95% CI 1.003 -1.008, P < .0001), need for blood transfusion (OR 3.32, 95% CI 1.687-6.528, P < .001), and multilevel fusion surgery (OR 1.142, 95% CI 1.007 -1.297, P < .04)., Conclusions: Older age, high BMI, living alone, high disability score, extended surgical time, blood transfusion, and multilevel fusion are significant factors that increase the odds of being discharged to facilities other than home., Level of Evidence: Level 3., Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

This study examined whether individuals undergoing total hip arthroplasty who are self-rated as "highly active", demonstrated higher pre-operative activity levels than others., Methods: 483 patients were retrospectively identified; 241 were "highly active" and 242 were not. They were compared using WOMAC, self-reported activity and 6-Minute Walk Test (6MWT)., Results: Self-reported highly active adults demonstrated statistically significant higher WOMAC scores (48.85 vs 43.79), increased mean number of activities performed and mean 6MWT (348.14 m vs 274.64 m)., Conclusions: The positive correlation between subjective and objective measures of mobility increase our confidence in the latter as valid indicator of patient's preoperative activity level.

Background: Simultaneous bilateral total hip arthroplasty (THA) is an attractive option for patients with osteoarthritis as it requires a single anesthetic and hospitalization. Nonetheless, serious concerns remain over the perioperative safety and rate of hospital readmission. The purpose of the present study was to compare the rate of 30-day major complications and hospital readmissions between patients undergoing simultaneous bilateral vs unilateral THA using the National Surgical Quality Improvement Program database., Methods: The National Surgical Quality Improvement Program database was queried from 2011 to 2015 inclusively to identify all cases of elective, primary simultaneous bilateral THA and match them to a control group of unilateral THA cases. A multivariable regression analysis was then used to assess the relationship of simultaneous bilateral vs unilateral THA on major complications and readmissions., Results: A total of 575 bilateral THA patients were matched to 2290 unilateral THA patients using a 4:1 ratio based on age, sex, and American Society of Anesthesiologists scores. Bilateral THA patients were more likely to undergo general anesthesia (77% vs 58.7%, P < .0001), required more postoperative transfusions (29.2% vs 15.9%, P < .0001) and were more often discharged to a rehabilitation facility rather than home (39.4% vs 20.8%, P < .0001). However, the adjusted odds of a major complication (odds ratio = 0.72, 95% confidence interval [0.41-1.24], P = .24) and 30-day readmission (odds ratio = 0.67, 95% confidence interval [0.38-1.19], P = .17) were similar between the 2 groups., Conclusion: Although patients who underwent simultaneous bilateral THA were more likely to be discharged to a rehabilitation facility and required significantly more perioperative transfusions compared to those undergoing unilateral THA, the odds of a 30-day major complication and readmission were similar between groups., Level of Evidence: III., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Objectives: Bone fracture healing is regulated by a series of complex physicochemical and biochemical processes. One of these processes is bone mineralization, which is vital for normal bone development. Phosphatase, orphan 1 (PHOSPHO1), a skeletal tissue-specific phosphatase, has been shown to be involved in the mineralization of the extracellular matrix and to maintain the structural integrity of bone. In this study, we examined how PHOSPHO1 deficiency might affect the healing and quality of fracture callus in mice., Methods: Tibial fractures were created and then stabilized in control wild-type (WT) and Phospho1 -/- mice (n = 16 for each group; mixed gender, each group carrying equal number of male and female mice) at eight weeks of age. Fractures were allowed to heal for four weeks and then the mice were euthanized and their tibias analyzed using radiographs, micro-CT (μCT), histology, histomorphometry and three-point bending tests., Results: The μCT and radiographic analyses revealed a mild reduction of bone volume in Phospho1 -/- callus, although it was not statistically significant. An increase in trabecular number and a decrease in trabecular thickness and separation were observed in Phospho1 -/- callus in comparison with the WT callus. Histomorphometric analyses showed that there was a marked increase of osteoid volume over bone volume in the Phospho1 -/- callus. The three-point bending test showed that Phospho1 -/- fractured bone had more of an elastic characteristic than the WT bone., Conclusion: Our work suggests that PHOSPHO1 plays an integral role during bone fracture repair and may be a therapeutic target to improve the fracture healing process. Cite this article : M. W. Morcos, H. Al-Jallad, J. Li, C. Farquharson, J. L. Millán, R. C. Hamdy, M. Murshed. PHOSPHO1 is essential for normal bone fracture healing: An Animal Study. Bone Joint Res 2018;7:397-405. DOI: 10.1302/2046-3758.76.BJR-2017-0140.R2., Competing Interests: Conflict of Interest Statement: None declared

Study Design: Retrospective cohort study., Objective: To identify patient or procedure related predictors of postoperative blood transfusions in posterior lumbar fusion (PSF)., Summary of Background Data: The rate of PSF surgery has increased significantly. It remains the most common surgical procedure used to stabilize the spine; however, the impact of blood loss requiring blood transfusions remains a significant concern., Methods: Analysis of data from the Canadian Spine Outcomes and Research Network. Patients who underwent PSF between 2008 and 2015 were identified. Multivariate analysis was used to identify predictors of blood transfusion from the collected information., Results: Seven hundred seventy two patients have undergone PSF, 18% required blood transfusion, 54.8% were females and the mean age was 60 years. The analysis revealed five significant predictors: American Society of Anesthesiologist class (ASA), operative time, multilevel fusion, sacrum involvement, and open posterior approach. The odds of transfusion for those with ASA >1 were 6 times those with ASA1 (odds ratio [OR] 6.1, 95% confidence interval [CI] 1.4-27.1, P < 0.018). For each 60-minute increase in operative time, the odds of transfusion increased by 4.2% (OR 1.007, 95% CI 1.004-1.009, P < 0.001). The odds of transfusion were 6 times higher for multilevel fusion (OR 5.8, 95% CI 2.6-13.2, P < 0.001). Extending fusion to the sacrum showed 3 times higher odds for blood transfusion (OR 3.2, 95% CI 1.8-5.8, P < 0.001). The odds of transfusion for patients undergoing open approach were 12 times those who had minimal invasive surgery (OR 12.5, 95% CI 1.6-97.4, P < 0.016). Finally, patients receiving transfusions were more likely to have extended hospital stay., Conclusion: ASA >1, prolonged operative time, multilevel fusion, sacrum involvement, and open posterior approach were significant predictors of blood transfusion in PSF., Level of Evidence: 3.

Purpose: Development of liver metastasis remains the most common cause of mortality in uveal melanoma (UM). A few cell lines cultured from primary UM tumors have been used widely to investigate the pathobiology of UM. However, the translation of basic knowledge to the clinic for the treatment of the metastatic disease has remained incremental at best. In this study, we examined whether the properties of UM cell lines at various passages were similar to their corresponding primary tumors., Methods: Gene expression profiling by microarray was performed on UM primary tumors and derived cell lines cultured at varying passages. Expression of UM protein markers was monitored by immunohistochemical analyses and Western blotting. The in vivo tumorigenic properties of UM cultures were evaluated using athymic nude mice., Results: Cell passaging severely reduced the expression of genes encoding markers typical of UM, including those of the prognostic gene signature. Marked differences between gene expression profiles of primary tumors and cell lines could be linked to the infiltrating immune and stromal cells in situ. In addition, the tumorigenic properties of UM cell lines also increased with cell passaging in culture as evaluated by their subcutaneous injection into athymic mice., Conclusions: Together, these findings demonstrate that the short-term UM primary cultures exhibit molecular features that resemble the respective surgical material and, thus, represent the best model for in vitro-assessed cancer treatments.

Bone is one of the most dynamic tissues in the human body that can heal following injury without leaving a scar. However, in instances of extensive bone loss, this intrinsic capacity of bone to heal may not be sufficient and external intervention becomes necessary. Several techniques are available to address this problem, including autogenous bone grafts and allografts. However, all these techniques have their own limitations. An alternative method is the technique of distraction osteogenesis, where gradual and controlled distraction of two bony segments after osteotomy leads to induction of new bone formation. Although distraction osteogenesis usually gives satisfactory results, its major limitation is the prolonged duration of time required before the external fixator is removed, which may lead to numerous complications. Numerous methods to accelerate bone formation in the context of distraction osteogenesis have been reported. A viable alternative to autogenous bone grafts for a source of osteogenic cells is mesenchymal stem cells from bone marrow. However, there are certain problems with bone marrow aspirate. Hence, scientists have investigated other sources for mesenchymal stem cells, specifically adipose tissue, which has been shown to be an excellent source of mesenchymal stem cells. In this paper, the potential use of adipose stem cells to stimulate bone formation is discussed.

Unlabelled: Balloon cell nevus is a rare histopathological lesion characterized by a predominance of large, vesicular and clear cells, called balloon cells. There is only 1 case of balloon cell nevus of the iris reported in the literature., Case Report: A 55 year-old man presented a pigmented elevated lesion in the right iris since the age of 12 years old. The lesion had been growing for the past 2 years and excision was performed. Histopathological examination showed a balloon cell nevus composed of clear and vacuolated cells without atypia. A typical spindle cell nevus of the iris was also observed. The differential diagnosis included xanthomatous lesions, brown adipocyte or other adipocytic lesions, clear cell hidradenoma, metastatic clear cell carcinoma of the kidney and clear cell sarcoma. The tumor was positive for Melan A, S100 protein and HMB45., Conclusion: Balloon cell nevus of the iris is rare but should be considered in the differential diagnosis of melanocytic lesions of the iris., (Copyright © 2014 Elsevier GmbH. All rights reserved.)

Hyperkalemia is a common condition encountered in medical and surgical patients. It can lead to various complications including cardiac arrhythmias. Sodium polystyrene sulfonate (SPS) in sorbitol is an ion-exchange resin that can be used to treat hyperkalemia. It can be used in enema or in oral form. The present article describes the case of an intensive care unit patient who experienced severe, diffuse, intestinal perforation induced by the use of SPS-sorbitol, requiring multiple laparotomies, followed by a brief review of the relevant literature and recommendations regarding the use of SPS-sorbitol.